Pre-LCI, it doesn't look like the 5 series ACC with Stop and Go actually brakes to a standstill. I am hoping the LCI model improves on that. I found an evaluation of several cars including the 5 series. BMW came next to last behind Volvo, MB and Audi. From that report:
"The AEBS in the BMW 5-series is not on a par with its competition. While the driver is warned very early, the initial alarm is too easy to ignore. If the driver fails to react to the warning, the BMW initiates partial braking, which does not reduce speed as effectively as the rival systems. If the obstacle is stationary, the BMW does not brake at all."
"The BMW does not come with an autonomous brake assist. If a collision is imminent, the car slightly aligns the brake shoes and improves braking response by priming the brakes. If, however, the driver applies inadequate brake pressure, it does not automati- cally adjust brake force to prevent the crash."
The full report is here:
http://www.activetest.eu/pdf/adac_aebs_report_en.pdf